Screw-holding screw driver



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INVENTOR, W 77 Thompson, Y

DJ TE- y v /Z ATTOHNEY.

V w. F. THOMPSON SCREW-HOLDING 'SCREW DRIVER Sept. 4, 1951 Dial- Patentet Sept. 4, 1951 UNITED STATES PATENT OFFICE .2566583 SCEEW-HOLDING SCREW DRVR y William F; Thompson, Salna, Kans.

Application December 13, 1946, Serial No. ?15,93'70 l 1 oaimf (o. 145-50) The present invention relates to screw drivers having means for holding the screw to the blade of the screw driver while starting a screw. screw drivers of this class may be roughly divided into two groups, those which hold the screw to the screw driver by jaw-like means which grip the head of the screw, and those which operate solely within the kerf of the' screw. It is to this latter group' that my inv'ention speeifical iy relates.

It has heretoiore been proposed to drill the shank of a screw' driver and` mount ther-ein a rod having a fiat end adjacent the edge of thevshanlr blade which rod when turned will tend to jam in the kerf and thereby hold the screw in place. All such screw drivers heretofore known to me are not who'lly reliable. The screw frequently falls oif.' i

My invention has for its principal object to overcome this defect in previous screw drivers and provide a positively-operative holding means.

A further object is to improve the general construction of the screw driver.

Again it is the object of the present invention to provide a screw driver of the kind above referred to that can be re-ground, re-shaped, etc., when worn, damaged or broken, i. e., can be ground back to its original shape without loss of toothed gripping edges on the inner rod.

With the above objects in View invention urreference being had to the accompanying drawing in which:

Figs. 1 and 2 are elevations 90 degrees apart showing my improved screw driver.

Fig. 3 is a longitudinal section of the same on the line 3-3 of Fig. 2.

Fig. 4 is a cross section on the line 4-4 of Fig. 3.

Fig. 5 is a cross section on the line 5--5 of Fig. 3.

Fig. 6 is a bottom end elevation of the screw driver.

Fig. '7 is an enlarged detail longitudinal gripping rod in its inactive position.

Fig. 8 is a View 1ike Fig. 7 with the gripping rod in its active position.

Fig. 9 is a detail elevatlon of the handle end of the shank.

In the drawing in which like numerals of reference indicate like parts in all the figures, l represents the shank of the screw driver, one end of which (the blade) is bevelled or tapered as at 2. The shank is drilled ongitud'nally to provide a bore 3 extending from one end to the other. That portion of the shankwhich is secured in the bore I? of the handle l l is also slotted lengthwise, as at 4, and is provided with a 90 cross s'lot 5, and an annular g'roove 6.

i represents a length of hard'ened wire rod which freely fits the bore 3 from the blade end of the shank to the groove 5 at which place it is bent at 'right angles as at ll! to li'e in' the' recess 20 of a knurled ring [9 that turns on the shank l. The rod 'i is threaded or knurled for a greater or lesser distance from its outer end as at 8 and it has two bevelled faces 9 that line up with the bevelled faces 2 when the rod is in its inactive position (Fig. 7). The' diameter of the rod 'i is slightly greater than the' screw Contacting 'edge of the blade of the' shank so that when the rod is in action the flat surfaces 9 will lie crosswise of the kerf as shown in Fig. 8.

The handle ll, in addition to the bore !2, has a counterbore [3 and a slot 22 to receive the torsion spring ZI, one end 23 of which lies against member n and the other end 21 of which lies in the slot 22. The spring 2l is for the purpose of holding rod member n seated in the slot 20 and to turn the rod into its active position.

The handle ll is also bored as at M to receive a latch bolt !5 and spring !6. A finger button screw !8 has a portion that passes through a slot ll in the handle and screws into the bolt !5 for Operating same. rhe knurled ring e has a suitaby located notch 24 to receive the outer end of the latch bolt I5 to hold the ring [9 in a position to hold rod 1 in its inactive position as shown in Fig. 3.

The shank may be secured in the handle Il in any approved way as by a rivet 25 and a split ring 26 is placed in groove 6 to hold ring !9 in place.

After placing a screw on the blade of the screw driver as shown in Fig. 7, button !8 is moved to release latch bolt 15 from notch 24 whereupon spring z will turn rod 1 to the active or screwholding position (Fig. 8). The diameter of the rod 1, being slightly greater than the width of the slot in the screw used results, when rod is turned within the slot, and sufiicient pressure applied (as by torsion spring 21) to such rotation, in a positive looking or holding of the screw upon the blade of the screw driver. The points of the threads or milling on the rod bite into the side walls of the kerf of the screw and thereby prevent accidental disconnection of the screw from the blade of the screw driver. Thus the holding of the screw upon the blade does not depend on the contact of a smooth corner edge of the rod as in previously known screw drivers of this general type, but the screw is firmly held on my tool by the action of the saw-tooth edges under the action of spring ZI. The degree of pressure applied by the spring tension rotating rod 'I governs the amount of bite applied to hold the screw.

The rod 'I may be knurled or threaded throughout its length if desired but only a portion equal to the length of the blade of the screw driver is sufiicient for all practical purposes.

In manufacturing my tool, it Would appear best that the blade, before shaping or grinding to form, should have the rod inserted therein and latched into position and both blade and rod ground and finished while such fixed relation to one another remains, This being done, it is clear that in such fixed position (normal or inactive position) the rod and blade are in form quite similar to the standard shaped screw driver blade. 4

The slotting of the shank at l permits bending over the end 10 of the rod 'I before assembling the rod and shank.

To release the screw it is only necessary to turn ring l9 backward (counter-clockwise in Fig. 5) until latch bolt 15 again enters recess 24.

From the foregoing description taken in connection with the accompanying drawing it is thought that the construction, operation and advantages Will be clear to 'those skilled in the art.

What I claim is:

In a screw driver, a handle having a central shank-receiving bore and a counter-bore, a tubular shank held With one end in said central bore said end being longitudinally slotted and provided with a cross slot merging with the longitudinal slot, a screw-gripping rod swivelly mounted in said tubular shank and having a right-angla'rly extended end located in said cross slot, a torsion spring in said counter-bore with one of its ends anchored to said handle and the other end engaging the end of said rod which lies in said cross slot and continuously tending to turn said rod in one directtion, a member rotatably mounted on said shank adjacent said handle and operatively connected to said rod for turning the rod against spring tension, and a latch device mounted on the handle and operatively engaging said rotatable member to hold it against turning under the spring action, the free end of said tubular shank and that of said rod being tapered to enter the kerf of a screw when said tapered portions of shank and rod are in aligmnent, said tapered end of the rod having means to grip the screw inits kerf when said rod is turned to disalign said tapered ends of the shank and rod, and means to hold said shank from turning in said handle.

WILLIAM F. T'HoMPsoN.

REFERENCES ITED The following references are of record in the le of this 'patent:

UNITED STATES PATENTS Number Name Date 1,063,304 Titus June 13, 1913 1,499,491 Weissbeck et al July 1, 1924 1,536,758 B'odmer May 5, 1925 1,781,470 Mueller Nov. 11, 1930 2,161,095 Schafier June 6, 1939 2,404,427 Bloomfield July 23, 1946 FOREIGN PATENTS Number Country Date 224.028 Great Britain Nov. 6, 1924 

